A new version (2.3) got released today on Steam and itch.io. Will it be also released on GOG?

You'll have to wait 2-6 weeks for it to clear though the Ministerstwo Przedsiębiorczości i Technologii.

As an alternative, if you don't want to wait (and don't have version 2.3 via other means, like from a bundle), you could try compiling the game from source.

In fact, if you want to run the game on a 32-bit or non-x86 platform, compiling the source is your only option to play 2.3.

yes. https://twitter.com/terrycavanagh/status/1432999437824049152

2.3.1 is now live on GOG.

I really like the inclusion of Glitchrunner mode (re-introduces glitches that were fixed in previous versions), though be aware that it is possible to get stuck (some of the bugs that Glitchrunner mode unfixes could have that effect).